Mabcel jean louis ledru anb edouabd joseph bachmann



Patented Apr. 7, 1925.

' UNITED STATES PATENT .o Price-1* 11mm. man LOUIS nnnnu 'mm EDOUABD 'Josarn BACHMANN, or noussrnnou.

r'mcn, sameness r rmcn.

SOCIFIJJE CHIHIQUE'DES USINES DU RHONE, 0F PARIS,

rnocnss roe 'rnn unu'uzmc'rmm or aon'rannnnrnn.

No Drawing.

To all whomit may concern:

Be it known that we, MARCEL J EAN LoUIs LEnnU, residin at Roussillon, Isere, France a citizen of t e Republic of France, and 'EDOUARD JOSEPH BACHMANN, residing at Roussillon, Isere, France, a citizen of the Confederation of Switzerland, have invented certain new and useful Improvements in Processes for the Manufacture of Acetaldeturned their efforts to extending oxygen'present, whet or provided by the-re hyde, of which the following is a specification.

Since Kutscheroft discovered that acetylene combines with water in the presence of mercury salts to produce acetaldehyde (Berichte 14, 1540 and 1713), numerous patents have been taken for the purpose of utilizing this reaction commercially. The hydrating process discovered by Kutscherotf stops after a while owing to reduction of the mercuric salt with formation of metallic mercury: Investigators havetherefore the duration of the reaction in introducing oxygen in the reacting liquid in order to oxidize the mercuric salt as it is reduced. In certain patents (D. R. P. 292,818, 293070 and 299,467), oxidizing agents, particularly ferric salts, are added. In others (D. R. P. 305,182), a mixture of acetylene and oxygen is passed through the solution of mercury salts. Others (D. R. I. 360,417 and 300,418) generate oxygen within the reacting mass by electrolysis of the catalytic agent; it is this latter method which is adopted in the French patent No. 491,466,- butwith a catalytic liquid containing ferrous sulphate in addition to" the mercuric salt.- The U; S. A; Patent No. 1,477,957 covers quite a. similar process: the catalyst is a sulphuric acid solution of ferrous and mercuric sulphate into which oxy en is introduced either y electrolysis or -'un e amolecular form in mixing. it with the acetylene.

We have noticed that/the hydration of the I acet lene and its transformation into acetalde yde are always accompanied by the formation of a little acetic acid, whatever be the catalytic ent used. This acetic, acid is formed wit ox gen. taken from the duction ofthe mercuric salt, or introduced in the molecular ,form, or with an oxydizing agent, or by electrolysis.

to 80 C.

Application filed September'tlti, 1824. Serial No. 739,798.

We have then sought to sul)sti tutc, in the liquid, this oxygen, which is abstracted by forming acetic acid, by causing acetylene mixed with air to pass through it. I started from metallic-mercury as mercurial lVe I constituent of the liquid, avoiding thereby the transformation of mercury into its salts, and we passed a stream of acetylene mixed with air throu h a sulphuric acid solution of ferrous sull iate containing mercury in sus ension. e hourly output of acetaldeby e was small. The acetylene was badly absorbed, and the oxygen introduced re- .oxidized the liquid badly. We then tried to catalyst remains active as long as the ab-' sorption is made to last, and the reaction appears to be practically without limits.

This process of manufacture gives an abundant continuous and regular production of acetaldehyde; the catalyst does not need to be regenerated, and the catalytic liquid is easy to prepare since it consists of metallic mercury (and not of mercury salts) of ferrous sulphate and of copper salts.

Emample,

In an apparatus adapted to be heated and rovided with a stirrer, are introduced the ollowin 4.3 kilogrammes sulphuric acid (100%), 1 kilogramme -ferrous sulphate (FeSOJ, 0.300 kilo ramme mercury, 0.150 kilogramme copper su phate (5H,O), 16 litres water.

A stream of acetylene with from 2 to 20% oxy n is bubbled through the mixture. The alde yde and the acid formed are extracted by any suitable process. -If purified acetylene is used, thehydration-has no limit, ro-

- vidcd that the mercury which may have een lene and oxygen througi an acid solution of ferrous sulphate in the presence of cop-.

per salts and of metallic mercury.

I 2. A process of manufacture of acct-aldehyde consisting in passing a stream of acetaldehyde and oxygen diluted with inert gases through an acid solution 'of ferrous sulphate in the presence of copper salts and of metallic mercury. I

3. A process of manufacture of acctaldes 1 hyde consisting in passing a stream of acetylene containing oxygen in the proportion of Y 2 to 20% through an acid solution of ferrous sulphate in the presence of copper salts and of metallic mercury.

4. A h-yde consisting in assin a stream of acetylene and oxygen t rough an acid solution of ferrous sulphate in the presence of copper sulphate and metallic mercury.

5. A process of manufacture of acetaldehyde consistingin passing a stream of acetylene and oxygen through an acid solution of ferrous sulphate in the presence of copper sulphate and metallic mercury heated to (i0'8() C.

In testimony whereof we have signed our names to this specification.

MAROEL JEAN LOUIS LEDRU.

EDOUARD JOSEPH BACHMA N N.

process of manufacture of acetalde- 4 

